Java – how do I read from a specific header in opencsv?

I have a CSV file I want to extract specific columns from it For example:

id1,caste1,salary,name1
63,Graham,101153.06,Abraham
103,Joseph,122451.02,Charlie
63,Webster,127965.91,Violet
76,Smith,156150.62,Eric
97,Moreno,55867.74,Mia
65,Reynolds,106918.14,Richard

How to use opencsv to read only the data in the header file caste1?

Solution

There is no built - in function in opencsv to read columns by name

Official FAQ example has the following examples on how to read from a file:

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
   // nextLine[] is an array of values from the line
   System.out.println(nextLine[0] + nextLine[1] + "etc...");
}

You only need to access rows using nextline [1] to get the values in the second column of each row (remember, the array index is based on zero)

So, in your case, you can simply read from the second line:

CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
   System.out.println(nextLine[1]);
}

For a more complex method of determining the column index from its title, see the answer from Scott Conway